mauryasankalp

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

A curated list of AWS resources to prepare for the AWS Certifications

A curated list of awesome AWS resources you need to prepare for the all 5 AWS Certifications. This gist will include: open source repos, blogs & blogposts, ebooks, PDF, whitepapers, video courses, free lecture, slides, sample test and many other resources.

Standard System Design Approach Template

Link : https://leetcode.com/discuss/career/229177/My-System-Design-Template [@Topcat]

(1) FEATURE EXPECTATIONS [5 min]

        (1) Use cases
        (2) Scenarios that will not be covered
        (3) Who will use
        (4) How many will use
        (5) Usage patterns

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	import java.util.SortedMap;
	import java.util.TreeMap;

	public class ConsistentHashing {

	// Consistent Hashing with Ring having 50 buckets.
	final static int LIMIT = 50;

	// Sorted Map.
	final static SortedMap<Integer, String> bucketIdToServer = new TreeMap<>();

	import java.io.IOException;
	import java.net.URL;
	import java.nio.file.Files;
	import java.nio.file.Paths;
	import java.util.ArrayList;
	import java.util.BitSet;
	import java.util.List;
	import java.util.concurrent.ThreadLocalRandom;
	import java.util.stream.Stream;

	public class AutoSuggestion {

	private static final int TEN_THOUSAND_REQUESTS = 10000;
	private static final int START = 0;
	private static final String SEPARATOR = "--------------------------------------------------------------------" +
	"---------------------------------------------------------------";

	public static void main(String[] args) {

	/*

	(() => {
	let count = 0;

	function getAllButtons() {
	return document.querySelectorAll('button.is-following') \|\| [];
	}

	async function unfollowAll() {
	const buttons = getAllButtons();